ES2638281T3 - Thrombectomy device - Google Patents

Abstract

Thrombectomy device with an essentially cylindrical stent structure (1) that has a plurality of meshes (3, 4), as well as two connectors (5, 5 ') arranged in different meshes (3) at the proximal end of the structure of stent (1), and a guidewire (2) having a coupling element (11) to which the connectors (5, 5 ') are coupled, characterized by a groove (7) that extends in a spiral by the enveloping surface (8) of the stent structure (1) and an extension stirrup (9) that crosses the groove (7) at the proximal end of the stent structure (1).

Description

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

DESCRIPTION

Thrombectoirna device

The invention relates to a thrombectomna device with an essentially cylindrical vascular stent structure that has a plurality of meshes, as well as two connectors arranged in different meshes at the proximal end of the stent structure, and a gma wire presenting a coupling element to which the connectors are coupled. The thrombectomy device is designed, in particular, to eliminate thrombi in the brain area, such as those frequently found in strokes, safely and without harm to the patient.

Thromboembolic diseases such as myocardial infarction, pulmonary embolism, peripheral thrombosis, embolisms of other organs, etc. they are normally caused by a thromboembol (abbreviated as a thrombus), that is, a viscoelastic blood clot formed by platelets, fibrinogen, coagulation factors, etc., which has been deposited in a blood vessel, totally or partially obstructing it. The obstruction of the arteries of organs causes the interruption of the supply of oxygen and nutrients to the dependent tissue. Shortly after the alteration of functional metabolism with loss of function, the structural metabolism is paralyzed with death of the affected tissue (infarction). The organs most frequently affected in humans are the heart and the brain. However, these alterations also affect the arteries of the extremities and the pulmonary arteries. Venous thrombosis and thromboembolic obstructions are also frequent in the veins of the legs and pelvis. The clinical picture of a thrombotic obstruction of an intracranial sinus can cause severe cerebral hemorrhages due to the alteration of venous drainage in brain tissue.

In view of the severity of the clinical conditions caused by thromboembolism and the frequency of these conditions, different techniques are known to dissolve or eliminate thrombi.

Thus, the treatment of these patients with thrombolytic agents, such as streptokinase or urukinase, or with anticoagulants, whose effect is thrombolysis or thrombus growth content, is known. Since these treatment procedures usually require a lot of time, they are often combined with procedures that are used to crush or medically remove the thrombus or embolus.

In addition to open surgical interventions, the use of transluminal or endovascular interventional therapeutic strategies guided by catheters is growing in the state of the art since they are less invasive. Thus, the removal of the thrombus from the patient's body is known by aspiration catheters that generate subatmospheric pressure, or mechanically with catheters provided with extraction baskets, spirals, hooks or the like (see US 6,245,089 B1; US 5,171,233 A1, Thomas E. Meier et al., Stroke 2002 (9) 2232).

The drawback of thrombolytic therapeutic procedures is that they are rarely successful once the time interval has elapsed. Frequently, the known transluminal devices are not able to completely eliminate a thrombus, there is also a risk that the thrombus or fragments of it will be released and transported by the bloodstream to vessels with a smaller lumen, where they are more difficult to reach and to try. In addition, due to their size and / or reduced flexibility, the devices known in the state of the art are not very suitable for removing thrombi from vessels with a particularly small or very tortuous lumen, such as those of the brain.

From WO 2004/008991 A1 a medical implant is known in the form of an open vascular endoprotesis intended for the treatment of aneurysms and other vascular malformations. With the help of a GMA wire, this implant is guided to the place of application, where it emerges. It has been proposed the use of this combination of implant and gma wire for the extraction of thrombi, suppressing by its nature the detachment of the implant part of the gma wire. The drawback of this implant and gma wire construction is, however, in that the tensile or elastic force is relatively reduced. The construction exerts a not always sufficient cutting action on the thrombus located in the vascular wall, so that remains remain in the vessel. The union to the gma wire through a structure that narrows (drop) causes, in particular, a narrowing of the proximal area of the structure under traction that reduces the efficiency of the construction. WO 2009/105710 A1 discloses a thrombectomna device with an essentially cylindrical vascular endoprosthetic structure that has a plurality of meshes, as well as two connectors arranged in different meshes at the proximal end of the vascular endoprosthetic structure, and a GMA wire presenting a coupling element to which the connectors are coupled. US 5618299 A discloses a vascular stent with a spiral groove. In view of the drawbacks of the state of the art, the aim of the invention is to provide a device for the removal of foreign bodies and thrombi from the blood vessels that allows, in particular, to remove thrombi from vessels with a small lumen, present a Good maneuverability in very tortuous vessels and has a large active surface.

This objective is achieved in accordance with the invention with a device of the type mentioned at the beginning which has a groove that spirally extends through the enveloping surface of the vascular endoprosthetic structure and which at the proximal end of the endoprosthetic structure vascular is crossed by a stirrup of

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

extension.

The device according to the invention consists of a cylindrical structure, such as that presented by vascular endoproses, with a plurality of meshes. It is connected through two connectors with a large wire that allows it to be placed precisely. The connectors are arranged at the proximal end in a mesh structure and end in a coupling element which in turn constitutes the distal end of the wire.

The term "proximal" used herein designates the side facing the doctor who performs the treatment, while "distal" is the side, for example of the structure of vascular endoprotesis or the large wire, away from the doctor.

The mesh structure of the vascular endoprotesis can be a braided structure, that is to say composed of individual wires, although preferably it is a cut structure in which the mesh structure is trimmed from a suitable diameter tube with the help of a To be. The material is usually a metal, although it can also be a plastic. It should have sufficient elasticity that allows it to contract the diameter of a usual catheter and, on the other hand, expand to the desired and predetermined diameter when released from the catheter.

As materials for vascular endoprotesis, in addition to iron alloys (stainless steel, spring steel) and cobalt-chromium alloys, shape memory alloys, such as binary alloys of nickel-titanium (nitinol) are considered ) and the ternary alloys of nickel-titanium-chromium (alloys doped with chromium). In the neurovascular field, nitinol is especially known for the application in self-expanding stenting structures.

The device according to the invention is, in principle, a flat structure wound in the form of a tube and having a groove that extends in the form of a spiral or helix through the enveloping surface of the structure of vascular endoprotesis. This groove may constitute a complete 360 ° or only partial spiral, for example about 180 ° or 120 °. The enveloping surface of the structure of vascular endoprotesis opens in the area of this groove, in which the width of the groove at the place of application is also determined by the lumen of the vessel since the structure of vascular endoprotesis, once released of the catheter, it can only be deployed to the extent permitted by the lumen of the vessel.

In order, on the one hand, to fix the structure of vascular endoprotesis spatially and, on the other, to provide it with a certain tension, an extension bracket extends over the groove at the proximal end of the structure of vascular endoprotesis. The extension stirrup increases the radial strength of the self-expanding structure but also serves to hold the opposite edges of the vascular endoprosthetic structure in position along the groove.

The thrombectoirin device according to the invention may have more extension stirrups in the central and distal areas, beyond the proximal extension stirrup. However, if materials with sufficient shape and prestressing are used, all extension stirrups can be dispensed with.

The thrombectomy device according to the invention is used by transporting it to the place of application by means of a catheter and releasing it there either in the actual thrombus or in the distal direction of the thrombus. The device expands in the vessel and adapts to the lumen of the vessel. The material of the thrombus is trapped in the mesh structure, either during extension or during removal, and is dragged when the device is removed to the catheter. Pieces of the thrombus attached to the vascular wall are dragged by means of the cutting action of the meshes and the edges along the groove. The thrombus is inserted into the catheter and removed from the body along with the catheter.

The spiral trajectory of the groove in the enveloping surface presents the special advantage for the thrombus removal that the edges of the structure of vascular endoprotesis along the groove travel under traction in a tangential direction along the penimeter of the vascular wall This improves the cutting action. At the same time it improves (reduces), thanks to the spiral trajectory, the resistance to bending in such a way that a better adaptation to the curved vessels can be achieved. This facilitates both the placement and removal of thrombi from complex vascular structures.

The proximal stirrup improves the trajectory of the radial force of the structure of vascular endoprotesis in the proximal area. In particular, the stirrup reduces the narrowing of the structure of vascular endoprotesis and the tensile stress that occurs during withdrawal to the catheter. At the same time, an additional detachment effect is obtained, such as that also exerted by the meshes and the edges of the structure of vascular endoprotesis.

The important thing, however, is in particular the improvement of the extension force in the proximal area that allows the optimal adaptation of the structure of vascular endoprotesis to the lumen of the vessel. At the same time it prevents the areas of vascular endoprotesis separated by the groove from moving relative to each other.

In order to be able to safely remove the structure of vascular endoprotesis together with the stirrup towards the catheter, the extension stirrup is oriented towards the distal end of the structure of vascular endoprotesis. This means that the arch of the stirrup is closed in the distal direction but forms in a proximal direction, together with the connectors, a loop

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

which converges on the coupling element similar to the hole in an extraction basket.

According to one variant, the structure of vascular endoprotesis according to the invention can be closed at the distal end by a mesh structure, so that the thrombotic material accumulates therein as in an extraction basket.

As already noted, the structure of vascular endoprotesis according to the invention is preferably cut from a cylindrical tube with the help of a laser. This makes it possible to give individual meshes a special cross section, for example square, rectangular or trapezoidal. In the rectangular and trapezoidal embodiments, the short side of the cross section can be located on the outer surface on one side and the long side on the other. It is preferred that the short side, both of the rectangle and, especially, of the trapezium, is oriented towards the vessel wall, which facilitates the penetration of the thrombus into the mesh structure and allows the thrombus mass to be effectively displaced during the expansion of the structure of vascular endoprotesis.

The connectors arranged at the proximal end of the vascular endoprosthetic structure range from the proximal alveoli adjacent to the groove to a coupling element, in which they converge. They are part of the structure of vascular endoprotesis, so they are composed of the same material.

The large wire of the thrombectoral device according to the invention is a common large wire, such as that used for endovascular and, in particular, neuro-radiological purposes. It ends distally in the coupling element, which in turn houses the proximal ends of the connectors.

The coupling element as such can be a simple welding point where the wire and connectors converge. However, it can also be a common coupling element that allows the release of the cylindrical vascular endoprosthetic structure, which is especially necessary when for medical reasons withdrawal is not indicated, for example because it causes damage to the patient. In this case, the structure of vascular endoprotesis can remain in the body as vascular endoprotesis and exert its function forming a channel in the thrombus; The mesh structure presses the thrombus against the vascular wall.

In the latter case, the coupling element is, for example, a mechanical coupling element suitable for releasing the connectors upon exiting the catheter. In the specialized bibliography numerous systems of this type are described. Hydraulic release systems are also described. Especially suitable are electrolytic shedding systems in which a piece susceptible to electrolytic corrosion is dissolved by the current action and undoes the junction between the structure of vascular endoprotesis and the large wire. According to a first variant, the coupling element may be configured in the form of such a part susceptible to electrolytic dissolution, and according to a second variant the connectors are provided with such a detachment point or a detachment element. separated that dissolves by the current action. Stainless steel elements, magnesium elements or cobalt-chromium alloys previously corroded are suitable as detachment elements. Such systems are described in the bibliography.

In the configuration of the proximal area of the cylindrical vascular endoprosthetic structure, a short embodiment of the connectors is preferred. The distance between the proximal end of the mesh structure and the coupling element must be short. On the one hand, the unused length of the device is shortened and, on the other, the tension in the recovery loop formed with the extension bracket at the proximal end of the structure is increased.

According to a special embodiment, the distal area of the cylindrical vascular endoprosthetic structure can be widened in a cone or trumpet shape to allow a good adaptation to the vessel's lumen in this area. When removing the thrombi from a vessel, it is important that the active area, that is, the contact of the surrounding surface with the vascular wall, be as wide as possible. The larger the contact surface, the greater the likelihood of removing the thrombus completely.

The large wire and / or the structure of vascular endoprotesis may be provided in the usual manner with radiopaque markers, for example in the form of spirals or sleeves.

The invention is explained in more detail by means of the attached drawings. They show:

Figure 1 a flat representation of a first variant of the structure of vascular endoprotesis according to the invention;

Figure 2 a spatial representation of the structure of vascular endoprotesis of Figure 1;

Fig. 3 a flat representation of a second variant of a structure of vascular endoprotesis according to the invention;

Figure 4 a spatial representation of the structure of vascular endoprotesis of Figure 3 with coupled large wire;

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

5 shows a perspective view of a structure of vascular endoprotesis according to the invention with two connectors;

Figure 6 a representation of the cross-sections of the structure of vascular endoprotesis and

Figure 7 a schematic representation of the thrombectoirin device according to the invention.

Figures 1 and 3 show two variants of a cylindrical vascular stent structure 1 according to the invention, with individual meshes 3 and 4 and connectors 5 and 5 '. The meshes 3 and 4 are of two different types, presenting some (3) a wavy shape and the other (4) a domed shape with two tips. These two ways, by cooperating, give the entire structure both stability and flexibility.

In the flat representation of drawings 1 and 3, the structure of vascular endoprotesis is crossed by a groove or channel 7 which, at the proximal end of the structure, is crossed by the extension stirrup 9. The groove 7 is delimited by the lateral surfaces 10 and 10 'of the mesh structure. The groove 7 does not run parallel to the longitudinal axis of the structure but obliquely with respect to the longitudinal axis, which in the spatial representation results in a spiral path along the enveloping surface (see Figures 2/4 ).

The representation in Figures 1 and 3 is a flat representation of the structure of vascular stent 1 cut; The spatial representations are shown in Figures 2 and 4. In the flat representation the meshes 3 are directly adjacent to the meshes 3 'in such a way that a tubular overall structure is obtained with a groove or channel 7 that surrounds approximately half of the enveloping surface 8.

The variants of Figures 1 and 3 differ in the form of connectors 5 and 5 ', which in the case of Figure 3 have a longer configuration and converge in a coupling element 11 (see Figure 4). The coupling element 11 can be, for example, a system susceptible to electrolytic corrosion that allows the structure of vascular endoprotesis 1 to be detached from the large wire 12 (see Figure 4). In the variant according to figure 2, two detachment elements 6, 6 'can be provided for electrolytic detachment.

Both embodiments have in common that the groove 7 is crossed by the stirrup 9. The stirrup 9 itself begins at the alveoli located at the edges 10, 10 'of the mesh construction and its arc is oriented towards the distal side of the structure of vascular endoprotesis. This allows the structure of vascular endoprotesis to be removed to a catheter without problems. Together with the adjacent connectors 5 and 5 'the clamping arch 9 forms a recovery loop or hole of an extraction basket that converges in the coupling element 11 (Figure 4). For this, the distal end of the structure of vascular endoprotesis can also be closed with a mesh structure.

In the representations of Figures 2 and 4, which constitute the spatial reproduction of the structures of vascular endoprotesis of Figures 1 and 3, the nerves of the structure of vascular endoprotesis located in the posterior face are clearly represented. The groove 7 is seen that passes under the clamping arch 9 at the proximal end of the structure and snakes to the right side around the enveloping surface 8 of the vascular endoprosthetic structure. The groove 7 ends at the distal end on the underside of the vascular endoprosthetic structure 1 and thus describes a rotation of approximately 180 °.

Figure 5 shows the spatial representation of a vascular endoprosthetic structure according to the invention in which the connectors 5 and 5 'are provided with inwardly directed hooks that fit into a corresponding housing of a coupling element 11 of a large wire. 12. While the coupling element together with the proximal end of the connectors 5 and 5 'is in a catheter, the vascular endoprosthetic structure 1 is coupled to the large wire. When sliding out of the catheter, the junction between the connectors 5, 5 'and the coupling element 11 disappears and the structure can remain as vascular endoprotesis in the vascular system. The decoupling, however, will only be performed in special (emergency) cases, for example when the device cannot be removed without problems to the catheter.

Figure 5 clearly shows the loop structure formed by the arc 9 and the connectors 5, 5 ', as well as the path of the nerves 12 of the vascular endoprosthetic structure along the enveloping surface 8, whose edges act on the thrombotic material to be removed and separated from the vascular wall.

Figure 6 shows the two preferred embodiments of the ribs 12 with rectangular and trapezoidal cross-section, in which the short side is oriented in each case towards the enveloping surface 8 of the structure of vascular endoprosis 1 or towards the vascular wall 13 These embodiments guarantee, on the one hand, the necessary stability of the mesh network and, on the other, a good cutting and displacement action on the thrombus.

Figure 7 schematically shows the construction of a thrombectomy device according to the invention, with the large wire 12, the coupling element 11, the proximal junction zone with the connectors 5, 5 ', the active zone with the enveloping surface 8 and the distal area 13 with a trumpet-shaped widening.

In the drawings, the same reference symbols designate the same circumstances.

Claims (13)

5 10 fifteen twenty 25 30 35 1. - Thrombectoirna device with an essentially cylindrical vascular stent structure (1) having a plurality of meshes (3, 4), as well as two connectors (5, 5 ') arranged in different meshes (3) at the proximal end of the stent structure (1), and a wire (2) having a coupling element (11) to which the connectors (5, 5 ') are coupled, characterized by a groove (7) that spirally extends over the enveloping surface (8) of the vascular endoprosthetic structure (1) and an extension stirrup (9) that crosses the groove (7) at the proximal end of the structure of vascular endoprotesis (1). 2. - Device according to claim 1, characterized in that it consists of a material with shape memory, preferably from nitinol or from a nickel-titanium-chromium alloy. 3. - Device according to claims 1 or 2, characterized in that the arch of the extension bracket (9) is oriented towards the distal end of the structure of vascular endoprotesis (1). 4. - Device according to claim 3, characterized in that the extension bracket (9) and the connectors (5, 5 ') they form a loop that converges on the coupling element (11). 5. - Device according to one of the preceding claims, characterized in that it has one or more stirrups (9) additional in the central and / or distal part of the structure of vascular endoprotesis (1). 6. - Device according to one of the preceding claims, characterized in that the endoprosthetic structure Vascular (1) is cut from a tube and has rectangular or trapezoidal cross sections of the nerves. 7. - Device according to claim 6, characterized in that the cross sections of the ribs form, with its short side, the enveloping surface (8) of the structure of vascular endoprotesis (1). 8. - Device according to one of the preceding claims, characterized in that the endoprosthetic structure Vascular (1) can be detached from the wire (2) by mechanical, hydraulic or electrochemical means. 9. - Device according to claim 8, characterized in that the coupling element (11) is configured in the form of detachment element. 10. - Device according to claim 8, characterized by two detachment points, preferably with electrochemical detachment. 11. - Device according to one of the preceding claims, characterized in that the coupling element (11) is peripherally arranged. 12. - Device according to one of the preceding claims, characterized in that the distal end of the Vascular endoprosthetic structure (1) widens in cone or trumpet form. 13. - Device according to one of the preceding claims, characterized by marker elements.